1. Field
The present disclosure relates to a tethering-type head-mounted display (HMD) device and a method for controlling the same.
2. Background
Recently, a wearable glass-type terminal configured to be mounted on part of a human body has been developed. Also, a glass-type terminal mounted on a user's head part may be classified as a head-mounted display (HMD).
A HMD refers to a display device which is worn on a user's head part and provides an image directly in front of user's eyes, by which the user may enjoy various-types of video content through an image that is perceived to be much greater than that of a television or other display device. Thus, an HMD offers a user a high level of immersion and entertainment when presenting content, and currently, due to the advancement of various stereoscopic video technologies, an HMD provides a more vivid sense of reality that a flat screen display, such as a television or the like, cannot provide.
Meanwhile, HMDs may be classified according to driving schemes. For example, according to whether a controller receiving a user input is separately provided, HMDs may be classified as a stand-type HMD or a tethering-type HMD. For example, the stand-type HMD may receive various user inputs through an input unit provided in the HMD itself.
Meanwhile, the tethering-type HMD may use a separate device serving as a controller, but the tethering-type HMD may be advantageously linked to the device serving as a controller. For example, the controller may be a smartphone, or the like. In this case, the tethering-type HMD links with the smartphone such that the tethering-type HMD may display data, or the like, stored in the smartphone, or display notification information regarding an event that occurs in the smartphone.
While being capable of providing a maximized sense of immersion when displaying content to a user, the HMD also has some practical limits. For example, the HMD achieves the immersion by providing an image directly before user's eyes, and when the HMD is used for more than a predetermined period of time, the HMD may cause various undesired effects, such as dizziness, amblyopia (i.e., vision in one or more both eyes is reduced), and the like. Thus, an HMD may be programmed with a recommended maximum usage time, and when the HMD is worn by a user for more than the maximum recommended usage time, the user may be informed accordingly, thereby discouraging use of the HMD for more than the recommended maximum usage time.
A user may be instructed to take off the HMD occasionally. For example, the user may be instructed to remove the HMD to (1) receive detailed information regarding an event sensed in the device serving as a controller; is (2) perform a function of a specific controller device related to the event (for example, transmission of a response message, placing a call, and the like); or (3) take a break after the HMD is continuously used for more than the recommended maximum usage time.
However, when the HMD is taken off, viewing of content is inevitably interrupted. Interruption of viewing of content may significantly reduce the user's sense of immersion. Thus, techniques for maintaining the user's sense of immersion when viewing content through an HMD, even when the HMD is occasionally taken off, are being actively researched.